(1) Field of the Invention
This invention relates to high speed punching apparatus and more particularly to punching and nibbling devices for cutting out portions of flat sheet material.
(2) Prior Art
Metal pallets have been recently devised so as to provide means for articulating several layers of shoe or fabric parts with respect to one another, wherein they may be stitched together by automatic sewing machines. The pallets are made from several layers of template-like sheet metal, hinged together at a common edge, as shown in U.S. Pat. No. 3,988,993. The sheet metal has cut-outs therein, which define the path to be followed by stitching needles. The cut-outs for these pallets may be done by hand, which is time consuming, and difficult to do accurately or they may be done expensivley by numerical controlled milling machines. Those machines are not always at a shoe or garment manufacturing facility, because of their expense, size and complexity. This thus requires a long lead time for changing a pattern on a pallet if a shoe or garment manufacturer wishes to do so. Other methods and machines may be utilized to manufacture the cut-outs in the sheet metal, by drilling or punching a hole in the material, then utilizing a nibbling machine or saw to cut out any particular pattern.
U.S. Pat. No. 3,760,676 shows a complex rotary drive punch machine for nibbling cut-outs in sheet material, comprising a clutch mechanism, thrust ball arrangements and other devices presenting a complicated apparatus.
U.S. Pat. No. 4,168,644 shows a punching and nibbling device which requires stopping of the operation to change tools before going ahead with the nibbling sequence. Similar relationships are shown in U.S. Pat. Nos. 4,241,631 and 3,988,829.
These machines represented by these patents do not permit a simple arrangement for punching and nibbling a cut-out in one or a series of pieces of sheet material.
It is an object of the present invention, to provide a combination punching and nibbling machine which will overcome the disadvantages of the prior art.
It is a further object of this invention, to provide a fast, repeatable and accurate machine for cutting out sections in sheet material, such as sheet metal, laminates, plastic or the like.